1. Field of the Invention
The present invention relates to an exposure technique for forming a projected image of a pattern on a substrate, and a technique for producing a device using the exposure technique.
2. Description of the Related Art
For example, when a device such as a semiconductor element or a liquid crystal display element (electronic device, microdevice) is produced, a projection exposure apparatus is used, which projects a pattern of a mask (reticle, photomask, etc.), via a projection optical system, onto a plate (glass plate or semiconductor wafer, etc.) coated with a resist. For example, a plate for producing the liquid crystal display element is increasingly large-sized. In recent years, a plate exceeding 2 m square is used. For example, if a projection optical system of 1× magnification is used for such a plate, the mask is large-sized as well. As the mask is more large-sized, the cost of the mask becomes higher, because the production steps are more complicated for large areal sizes, while it is also necessary to maintain the flatness of the mask substrate. Further, for example, in order to form a thin film transistor portion of the liquid crystal display element, it is necessary to use masks in an amount corresponding to four to five layers in ordinary cases, which requires an enormous cost.
In view of the above, for example, a scanning type projection exposure apparatus (scanning type exposure apparatus) has been suggested, wherein a pattern of the mask is made to be small-sized as compared with the plate, by using a magnifying multilens system including a plurality of partial projection optical systems which are arranged in a divided manner in two arrays in the scanning direction, which are arranged adjacently in a direction perpendicular to the scanning direction (hereinafter referred to as “non-scanning direction”), and each of which has a magnifying magnification (see, for example, Japanese Patent Application Laid-open No. 11-265848). In the conventional scanning type exposure apparatus provided with the magnifying multilens system, the pattern of the mask is divided into a plurality of pattern areas in a strip-shaped form (stripped form) corresponding to the partial projection optical systems, respectively. Projected images of patterns in the respective pattern areas are transferred onto the plate, while being stitched with each other in the non-scanning direction, by one time of the scanning exposure. The phrase “transferred while being stitched with each other” means that the boundary portions in the non-scanning direction of the adjacent pattern projected images are transferred while being overlaid with each other.